The Colorado (CO) state sales tax rate is currently 2.9%. Depending on local municipalities, the total tax rate can be as high as 10.4%.

Colorado is a “home rule” state. Local-level tax rates in the state of Colorado are quite complex compared against local-level tax rates in other states. Colorado sales tax can be levied at the city/county/school/transportation and SPD (special purpose district) levels.

For sales tax registration, Colorado switched systems in October 2010. According to the Colorado Department of Revenue, all businesses must be using a number known as the new Colorado Account Number, which is eight digits. Numbers obtained prior to October 2010 are seven digits. In order to increase the accuracy of tax records, all businesses with seven digit numbers should add a “0” at the beginning of those original numbers. For example, if your account number was L12-34567-0000, your new number is 01234567.

Companies doing business in Colorado need to register with the Colorado Department of Revenue. In addition, a number of municipalities require registration for the purposes of collecting sales tax.

Filing frequencies are determined by the amount of sales tax collected each month. Most companies (with monthly sales tax collections of more than $300) must file monthly on or before the 20th of the month following reporting period.

Trustfile --
Avalara TrustFile provides detailed sales tax reporting for online sellers. Allowing businesses to know exactly where, when and how much to file. Ecommerce business owners can use TrustFile to determine whether or not they are collecting the right amount of sales tax in each individual state, and then store a record of their sales tax history securely in the cloud for free.